Shears for cutting sheet metal and the like.



l. HULTMAN.

SHEARS FOR CUTTING SHEET METAL AND THE LIKE. APPLICATION FILED NOV. 20,1916.

1,284,688. Patented Nov. 12,1918.

2 SHEETS-SHEET 1.

!. HULTMAN.

SHEARS FOR CUTTING SHEET METAL AND THE LIKE.

APPLICATION FILED NOV. 20, I9I6.

1,284,688. Patented Nov. 12, 1918.

2 SHEETS-SHEET 2- IVAR HULTMAN, 0F NEGLINGE SALTSJfiIBADEN, NEARSTOCKHOLM, SWEDEN.

SHEARS FOR CUTTING SHEET METAL AND THE LIKE.

Specification-of Letters Patent.

Patented Nov. 12, 1918.

Application filed November 20, 1916. Serial No. 132,418.

To all whom it may concern:

Be it known that I, IVAR I-IUL'rarAN, a subject of the King of Sweden,residing at Neglinge Saltsjiibaden, near Stockholm, in the Kingdom ofSweden, have lnvented a new and useful Shears for Cutting Sheet Metaland the like, of which the following is a specification.

This invention has for its object to essentially increase the cuttingpower of shears so as to enable one to out even thicker sheetmetal bymeans of hand-shears.

For this purpose one of the jaws is pivoted to its handle and betweenthe two handles is inserted a mechanism which strongly increases theleverage.

On the drawing which shows two embodiments intended to serve as examplesFigure 1 is a side view of one form and Figs. 2 and 3 side view and planview of the other form.

Fig. 4 shows a detail.

The jaws 1 and 2 are pivoted together at a.

The lower jaw 1 is integral with its handle 7. The upper jaw 2 ispivoted to its handle 3 at b and is also pivoted to the lever mechanismat c.

In Fig. 1 the lever mechanism consists of a segment 4, the rear concaveedge of which rests upon the convex edge of an eccentric 5 pivoted at (Zto the lower handle or to a lug 6 on said handle.

The points (6 b 0 (Z should be so disposed that a right line drawn from(r to b will be about perpendicular to a right line drawn from b to (Z,while the point 0 will be on or a little above the latter line.

When the shears is open. the point 0 is a little above the right lineb(Z. By pressing the handles together so that 3 moves to ward 7 thepoint 0 will approach said line until it reaches the same and by thismovement the distance between 6 and (Z will be increased, so as to beequal with the distance Z)c plus c-(Z, which is larger than distance b(Zwhen the points I), 0, (Z are the vertices of a triangle. The points aand (Z are however fixed and thus the increase of distance b(Z will meanthat point 6 is forced forward so as to swing the jaw 2 on pivot (z insuch a direction, that the shears will close a little.

WVhen slackening the pressure on the handles, a spring 71 will swing thehandle 3 upward so as to bring point 0 a distance above line b(Z,whereby the eccentric 5 is allowed to swing a little in direction of thearrow either bv means of its weight or by the action of a spring f so asto maintain the contact with segment 4. When then again compressing thehandles the jaw 2 is closed a little more. This action may be repeateduntil the shears is fully closed. For opening it the eccentric must beswung in opposite direction which maybe done by pressing down its rearend 51 by afinger.

It is obvious that the segment 4 and eccentric 5 act as an integral linkbetween the pivots 0 and (Z when the shears is compressed, and that thesegment should not slide upon the eccentric during such action. Toprevent such sliding the contact faces between segment 4 and eccentric 5may be unpolished or rough, if necessary.

As the distance between point 0 and line b-(Z is small, the leverage isa suitable one for overcoming high resistances.

In Fig. 2 the upper handle 3 or a lug 31 thereon is pivoted to a link 13(at c), the front end ofwhich is pivotally connected to a support 9 onthe lower handle 7.

This support 9 is free to move along the handle 7 in one direction butwill be locked in every position when a pull rearward is exerted on itsfree end (Z.

In the example shown the support 9 has a hole 10 so as to be passed onhandle 7 said hole being more wide than the thickness of the handle sothat the support can take a rearwardly inclined position and therebylock itself on the handle. A spring 11 tends to move the supportforward.

In the position shown the shears is fully open. The points 6, 0. d arethen on a right line. When pressing down the upper handle the point 0will move along a bow with radius c(Z on the fixed center (Z, and thepoint I) will move along a bow with radius ab on the fixed center a. Theresult is that point 7) is forced forward a little with an almostunlimited force so as to close the jaws a certain amount. This effect isdue to the fact that the points Z), c, d will be the vertices of atriangle instead of lying at a right line, and as any two sides of atriangle taken together are always greater than the third side and astwo of the sides viz. b-c and c(Z are constant, the distance b(Z, whichrepresents the third side, must increase. The point (Z is howeverstationary and thus the point 5 must move.

ll hen then lifting the handle 3 (which may be done automatically bymeans of a spring such as T1) the point Z) will keep its position andthe point 0 will rise until all three points are again on a right line.This will cause a little movementforwardof point (I (it 7) bestationary) so as to release the support 9 and allow it to be movedforward by means of its spring 11. By now pressing down the handle 3 thejaws will. be closed another amount. By such repeated movement of handle3 up and down the jaws will be successively closed until their tipsreach each other; and every time the applied power from the hand will beenormously multiplied.

The possibility of fully closing the jaws is of great advantages forinstance when cutting a piece bent into angular shape.

The jaws are opened by pulling the support 9 rearward. The support 9 isautoi'naticall y locked on handle 7 as soon as the link 13 begins topull in the direction u-c.

To prevent the handle 3 of Fig. 1- from sliding sidewise so as to bereleased from jaw 2 and segment a a piece 32 of sheet metal may be fixedon each side of handle 3 as indicated by dotted lines. Or the bearing insegment 4-. for the pivot 0 may be closed on both sides. It the segmentis made in two symmetrical halves these side walls of the bearing may le integral with the segment, or else one of them may torn: a separatelid. The segment l may have side flanges or lugs which overlap theeccentric or vice versa. Or the segment may have a central flange or ribwhich engages groove on'the edge of the eccentric or vice versa. 7

I claim:

1. Shears oi the character described, comprising in combination with thetwo cutting jaws, a handle rigidly secured to its aw and a handlepivotally secured to the other jaw, and a support adapted to movesuccessively along one of said handles during the opening and closingmovements of said handles, a link pivoted to the other of said handlesand to said support for successively advancing the pivoted handle bychanging the position oi its tulrruin support, substantially asdescribed.

Shears of the character described comprising in combination, two cuttingjaws, a handle rigidly secured to its iaw anr other handle pivotallysecured to the other jaw, a support having a hole through which one otsaid handles is passed and adapted to successively move along thishandle, said support being adapted to automatically lock itself bytaking up an inclined position to its handle, and a link pivoted to theother handle and to said support for successively advancing the pivotedhandle by changing the position of its fulcrum support, substantially asdescribed.

3. Shears of the character described, com prising in combination, twocutting jaws, a handle rigidly secured to its jaw, and a handlepivotally secured to the other jaw. and a support adapted to movesuccessively along one oi said handles during the opening and closingmovements of said handles, a spring adapted to move said support forwardwhen the handles are opened, and a link pivoted to the other of saidhandles and 75 to said support for successively advancing the pivotedhandle by changing the position of its fulcrum support, substantially asdescribed.

IVAR HULTMAN.

Witnesses L. HOWELL, FRANK LYON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, 20. G.

